In this section:

The two-loop explosion

During the past two years there has been a burst of activity in next-to-next-to-leading order (NNLO) calculations to make sure theory keeps up with experiment. Underpinning the prediction of LHC observables are perturbative computations of cross-sections, and NLO corrections have already been calculated for a large class of these processes relevant to the LHC program. Thanks to the impressive precision now being attained by the LHC experiments, however, we are now being taken into the complex realm of higher-order calculations, with an explosion of activity in recent months.